Cannabinoids are a class of specialized compounds synthesized by Cannabis. They are formed by condensation of terpene and phenol precursors. They include these more abundant forms: Delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabichromene (CBC), and cannabigerol (CBG). Another cannabinoid, cannabinol (CBN), is formed from THC as a degradation product and can be detected in some plant strains. Typically, THC, CBD, CBC, and CBG occur together in different ratios in the various plant strains.
Cannabinoids are generally classified into two types, neutral cannabinoids and cannabinoid acids, based on whether they contain a carboxyl group or not. It is known that, in fresh plants, the concentrations of neutral cannabinoids are much lower than those of cannabinoid acids. One strain Cannabis sativa contains approximately 61 compounds belonging to the general class of cannabinoids. These cannabinoids are generally lipophilic, nitrogen-free, mostly phenolic compounds, and are derived biogenetically from a monoterpene and phenol, the acid cannabinoids from a monoterpene and phenol carboxylic acid, and have a C21 to base material.
Cannabinoids also find their corresponding carboxylic acids in plant products. In general, the carboxylic acids have the function of a biosynthetic precursor. For example, these compounds arise in vivo from the THC carboxylic acids by decarboxylation the tetrahydrocannabinols Δ9- and Δ8-THC and CBD from the associated cannabidiol. As generally shown in FIG. 28, THC and CBD may be derived artificially from their acidic precursor's tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) by non-enzymatic decarboxylation.
Cannabinoids are widely consumed, in a variety of forms around the world. Cannabinoid-rich preparations of Cannabis, either in herb (i.e. marijuana) or resin form (i.e., hash oil), are used by an estimated 2.6-5.0% of the world population (UNODC, 2012). Cannabinoid containing pharmaceutical products, either containing natural cannabis extracts (Sativex®) or the synthetic cannabinoids dronabinol or nabilone, are available for medical use in several countries
As noted above, Δ-9-tetrahydrocannabinol (also known as THC) is one of the main biologically active components in the Cannabis plant which has been approved by the Food and Drug Administration (FDA) for the control of nausea and vomiting associated with chemotherapy and, more recently, for appetite stimulation of AIDS patients suffering from wasting syndrome. The drug, however, shows other biological activities which lend themselves to possible therapeutic applications, such as in the treatment of glaucoma, migraine headaches, spasticity, anxiety, and as an analgesic.
Indeed, it is well documented that agents, such as cannabinoids and endocannabinoids that activate cannabinoid receptors in the body modulate appetite, and alleviate nausea, vomiting, and pain (Martin B. R. and Wiley, J. L, Mechanism of action of cannabinoids: how it may lead to treatment of cachexia, emesis and pain, Journal of Supportive Oncology 2: 1-10, 2004), multiple sclerosis (Pertwee, R. G., Cannabinoids and multiple sclerosis, Pharmacol. Ther. 95, 165-174, 2002), and epilepsy (Wallace, M. J., Blair, R. E., Falenski, K. W W., Martin, B. R., and DeLorenzo, R. J. Journal Pharmacology and Experimental Therapeutics, 307: 129-137, 2003). In addition, CB2 receptor agonists have been shown to be effective in treating pain (Clayton N., Marshall F. H., Bountra C., O'Shaughnessy C. T., 2002. CB1 and CB2 cannabinoid receptors are implicated in inflammatory pain. 96, 253-260; Malan T. P., Ibrahim M. M., Vanderah T. W., Makriyannis A., Porreca F., 2002. Inhibition of pain responses by activation of CB(2) cannabinoid receptors. Chemistry and Physics of Lipids 121, 191-200; Malan T. P., Jr., Ibrahim M. M., Deng H., Liu Q., Mata H. P., Vanderah T., Porreca F., Makriyannis A., 2001. CB2 cannabinoid receptor-mediated peripheral antinociception. 93, 239-245; Quartilho A., Mata H. P., Ibrahim M. M., Vanderah T. W., Porreca F., Makriyannis A., Malan T. P., Jr., 2003. Inhibition of inflammatory hyperalgesia by activation of peripheral CB2 cannabinoid receptors. Anesthesiology 99, 955-960) and multiple sclerosis (Pertwee, R. G., Cannabinoids and multiple sclerosis, Pharmacol. Ther. 95, 165-174, 2002) in animal models.
More recently, several states have approved use of Cannabis and cannabinoid infused products for both recreational and medical uses. As these new medical and commercial markets have developed, there has grown a need to develop more efficient production and isolation of cannabinoid compounds. Traditional methods of cannabinoid production typically focus on extraction and purification of cannabinoids from raw harvested Cannabis. However, traditional cannabinoid extraction and purification methods have a number of technical and practical problems that limits its usefulness.
Limitations of Traditional Cannabinoid Production and Extraction Methods
For example, in U.S. Pat. No. 6,403,126 (Webster et al.), cannabinoids, and other related compounds are isolated from raw harvested Cannabis and treated with an organic solvent, typically a petroleum derived hydrocarbon, or a low molecular-weight alcohol to solubilize the cannabinoids for later isolation. This traditional method is limited in that it relies on naturally grown plant matter that may have been exposed to various toxic pesticides, herbicides and the like. In addition, such traditional extraction methods are imprecise resulting in unreliable and varied concentrations of extracted THC. In addition, many Cannabis strains are grown in hydroponic environments which are also not regulated and can results in the widespread contamination of such strains with chemical and other undesired compounds.
In another example, US Pat. App. No. 20160326130 (Lekhram et al.), cannabinoids, and other related compounds are isolated from raw harvested Cannabis using, again, a series of organic solvents to convert the cannabanoids into a salt, and then back to its original carboxylic acid form. Similar to Webster, this traditional method is limited in that is relies on naturally grown plant matter that may have been exposed to various toxic pesticides, herbicides and the like. In addition, the multiple organic solvents used in this traditional process must be recovered and either recycled and/or properly disposed of.
Another traditional method of cannabinoid extraction involves the generation of hash oils utilizing supercritical carbon-dioxide (sCO2). Under this traditional method, again the dried plant matter is ground and subjected to a sCO2 extraction environment. The primary extract being initially obtained and further separated. For example, as generally described by CA2424356 (Muller et al.) cannabinoids are extracted with the aid of sCO2 under supercritical pressure and temperature conditions and by the addition of accessory solvents (modifiers) such as alcohols. Under this process, this supercritical CO2 evaporates and dissolves into the cannabinoids. However, this traditional process also has certain limiting disadvantages. For example, due to the low solubility in supercritical sCO2, recovery of the cannabinoids of interest is inconsistent. Additionally, any solvents used must be recycled and pumped back to the extractor, in order to minimize operating costs.
Another method utilizes butane to extract cannabinoids, in particular high concentrations of THC, from raw harvested Cannabis. Because butane is non-polar, this process does not extract water soluble by-products such as chlorophyll and plant alkaloids. That said, this process may take up to 48 hours and as such is limited in its ability to scale-up for maximum commercial viability. The other major drawback of traditional butane-based extraction processes is the potential dangers of using flammable solvents, as well as the need to ensure all of the butane is fully removed from the extracted cannabinoids.
Another limiting factor in the viability of these traditional methods of cannabinoid extraction methods is the inability to maintain Cannabis strain integrity. For example, cannabanoids used in medical and research applications, or that are subject to controlled clinical trials, are tightly regulated by various government agencies in the United States and elsewhere. These regulatory agencies require that the Cannabis strains remain chemically consistent over time. Unfortunately, the genetic/chemical compositions of the Cannabis strains change over generations such that they cannot satisfy regulatory mandates present in most clinical trials or certified for use in other pharmaceutical applications.
Several attempts have been made to address these concerns. For example, efforts have been made to produce cannabinoids in genetically engineered organisms. For example, in U.S. patent application Ser. No. 14/795,816 (Poulos, et al.) Here, the applicant claims to have generated a genetically modified strain of yeast capable of producing a cannabinoid by inserting genes that produce the appropriate enzymes for its metabolic production. However, such application is limited in its ability to produce only a single or very limited number of cannabinoid compounds. This limitation is clinically significant. Recent clinical studies have found that the use of a single isolated cannabinoid as a therapeutic agent is not as effective as treatment with the naturally-occurring “entourage” of primary and secondary cannabinoids associated with various select strains.
Additional attempts have been made to chemically synthesize cannabinoids, such as THC. However, the chemical synthesis of various cannabinoids is a costly process when compared to the extraction of cannabinoids from naturally occurring plants. The chemical synthesis of cannabinoids also involves the use of chemicals that are not environmentally friendly, which can be considered as an additional cost to their production. Furthermore, the synthetic chemical production of various cannabinoids has been classified as less pharmacologically active as those extracted from plants such as Cannabis sativa. 
Efforts to generate large-scale Cannabis cell cultures have also raised a number of technical problems. Chief among them is the fact that cannabinoids are cytotoxic. Under natural conditions cannabinoids are generated and then stored extracellularly in small glandular structures called trichomes. Trichomes can be visualized as small hairs or other outgrowths from the epidermis of a Cannabis plant. As a result, in Cannabis cell cultures, the inability to store cannabanoids extracellularly means any accumulation of cannabinoids would be toxic to the cultured cells. Such limitations impair the ability of Cannabis cell cultures to be scaled-up for industrial levels of production.
Cannabinoid Biosynthesis Toxicity Limits In Vivo Production Systems
Efforts to generate Cannabis strains/cell cultures that produce or accumulate high-levels of cannabinoids have raised a number of technical problems. Chief among them is the fact that cannabinoid synthesis produces toxic by-products. Notably, both CBDA and THCA synthases require molecular oxygen, in conjunction with a molecule of FAD, to oxidize Cannabigerolic acid (CBGA). Specifically, as shown in FIG. 29, two electrons from the substrate are accepted by an enzyme-bound FAD, and then transferred to molecular oxygen to re-oxidize FAD. CBDA and THCA are synthesized from the ionic intermediates via stereoselective cyclization by the enzymes. The hydride ion is transferred from the reduced flavin to molecular oxygen, resulting in the formation of hydrogen peroxide and re-activation of the flavin for the next cycle. As a result, in addition to producing CBDA and THCA respectively, this reaction produces hydrogen peroxide (H2O2) which is naturally toxic to the host cell. Due to this production of a toxic hydrogen peroxide byproduct, cannabinoid synthesis generates a self-limiting feed-back loop preventing high-level production and/or accumulation of cannabinoids in in vivo systems. One way that Cannabis plants deal with these cellular cytotoxic effects is through the use of trichomes for Cannabinoid production and accumulations.
Cannabis plants deal with this toxicity by sequestering cannabinoid biosynthesis and storage extracellularly in small glandular structures called trichomes as note above. For example, THCA synthase is a water soluble enzyme that is responsible for the production of THC. For example, THC biosynthesis occurs in glandular trichomes and begins with condensation of geranyl pyrophosphate with olivetolic acid to produce cannabigerolic acid (CBGA); the reaction is catalyzed by an enzyme called geranylpyrophosphate:olivatolate geranyltransferase. CBGA then undergoes oxidative cyclization to generate tetrahydrocannabinolic acid (THCA) in the presence of THCA synthase. THCA is then transformed into THC by non-enzymatic decarboxylation. Sub-cellular localization studies using RT-PCR and enzymatic activity analyses demonstrate that THCA synthase is expressed in the secretory cells of glandular trichomes, and then is translocated into the secretory cavity where the end product THCA accumulates. THCA synthase present in the secretory cavity is functional, indicating that the storage cavity is the site for THCA biosynthesis and storage. In this way, the Cannabis is able to produce cannabinoids extracellularly and thereby avoid the cytotoxic effects of these compounds. However, as a result, the ability to access and chemically alter cannabinoids in vivo is impeded by this cellular compartmentalization.
To address these concerns, some have proposed chemically modifying cannabinoid compounds to reduce their cytotoxic effects. For example, Zipp, et al. have proposed utilizing an in vitro method to produce cannabinoid glycosides. However, this application is limited to in vitro systems only. Specifically, as noted above, cannabinoid synthase enzymes, such as THCA synthase, are water soluble proteins that are exported out of the basal trichome cells into the storage compartment where it is active and catalyzes the synthesis of THCA. Specifically, in order to effectively mediate the cellular export of such cannabinoid synthase, this enzyme contains a 28 amino acid signal peptide that directs its export out of the cell and into the extracellular trichrome where cannabinoid synthesis occurs. As a result of this signal-dependent extracellular compartmentalization of, in this instance, THCA synthase, this means that the THCA is made outside of the cytoplasm and would not be accessible to genetically engineered glycosylation enzymes. As such, simple expression of a UDP glycosyltransferase in plant cells, as vaguely alluded to in Zipp, et al., would not result in effective glycosylation of cannabinoid molecules in the compartmentalized and extracellular trichrome structure where cannabinoid synthesis occurs. Neither can the method of Zipp generate acetylated cannabinoids, as well as 0 acetyl glycoside cannabinoid molecules.
The foregoing problems regarding the production, detoxification and isolation of cannabinoids may represent a long-felt need for an effective—and economical—solution to the same. While implementing elements may have been available, actual attempts to meet this need may have been lacking to some degree. This may have been due to a failure of those having ordinary skill in the art to fully appreciate or understand the nature of the problems and challenges involved. As a result of this lack of understanding, attempts to meet these long-felt needs may have failed to effectively solve one or more of the problems or challenges here identified. These attempts may even have led away from the technical directions taken by the present inventive technology and may even result in the achievements of the present inventive technology being considered to some degree an unexpected result of the approach taken by some in the field.
As will be discussed in more detail below, the current inventive technology overcomes the limitations of traditional cannabinoid production systems while meeting the objectives of a truly effective and scalable cannabinoid production, modification and isolation system.